Determination of blood lead in dried blood-spot specimens by Zeeman-effect background corrected atomic absorption spectrometry.

A simple procedure for the determination of blood-lead levels in dried blood-spot filter-paper specimens is described. A 3/16 inch dried blood spot was analysed by a method involving extraction of the lead into 1.25% (NH4)2HPO4-0.5% Triton X-100 solution. A matrix-based calibration was used for analysis, with use of a Zeeman-effect background corrected atomic absorption spectrometer. The within-run precision (% relative standard deviation) of the method at the low end of the analytical range was 19% at 0.36 mumol dm-3 and 14% at 0.60 mumol dm-3. The accuracy of the method was verified by recovery tests and by comparison with a routine whole-blood method. The mean blood lead level of 425 Toronto newborns was 0.19 mumol dm-3 (range 0-0.75 mumol dm-3).